The present invention relates to an electronic switch and, more particularly, to an electronic switch designed for quick, automatic, reflex like response to current overloads.
Three types of electronic switches are widely used in the art. The first includes a relay. The second includes a semiconductor. Whereas the third includes both a relay and a semiconductor connected in parallel. Each of these switches has characterizing drawbacks.
Due to its high resistance during service the semiconductor of semiconductor based electronic switches consumes a great amount of energy, heats, and therefore requires a heat dissipation unit to dissipate the heat it generates during service.
Furthermore, the control unit (CPU) of such a semiconductor is not quick enough to substantially immediately monitor and respond to a sudden elevation in the current load, which may lead to a damage to the semiconductor itself and/or to other components of the circuit. Typical response time is in the range of 20-30 milliseconds.
The relay of relay based switches is designed to hold high current loads, associated, for example, with a shortage in the circuit and is therefore bulky and robust.
As before, the control unit (CPU) of such a relay is not quick enough to immediately monitor and respond to a sudden elevation in the current load, which may lead to a damage to the relay itself and/or other components of the circuit. Typical response time is in the range of 20-30 milliseconds.
Furthermore, a spark formation is associated with connecting/disconnecting the contacts of the relay, which results in accumulative damage to the switch which leads to low fidelity.
Under high current overload conditions (e.g., short current) the spark releases an immense amount of heat, which may result in melted contacts, and some times even fire and complete destruction of the switch.
In relay-semiconductor combined switches the spark problem is solved under normal service conditions, however, the CPU of these components faces a serious problem of monitoring the operation state (on or off) of the relay and/or semiconductor since they are connected in parallel. Only when both these components are in the off state, the CPU can assure that this is indeed the case.
The slow monitoring time affects the duration of control and extends the time required for decision making and response. This, in turn, is a major disadvantage in cases of a current overload that can damage the switch or other components of the circuit. Typical response time is in the range of 20-30 milliseconds.
Thus, a common drawback associated with all three prior art switches is the delayed response to a sudden and unexpected elevation in the current load, which latent response may result in a damage to the circuit due to the current load elevation.
It will be appreciated that as the duration along which the relay and/or the semiconductor are subjected to current overload shortens, the consumption which develops is smaller, thereby decreasing the damage.
There is thus a widely recognized need for, and it would be highly advantageous to have, an electronic switch designed for quick and automatic response to current overloads.